<h2>vm_read</h2><hr><p><strong>Function</strong> - Read the specified range of target task's address space.
<h3>SYNOPSIS</h3><pre><strong>kern_return_t vm_read</strong><strong>(vm_task_t</strong><var>target_task</var>,
<strong>vm_address_t</strong><var>address</var>,
<strong>vm_size_t</strong><var>size</var>,
<strong>size</strong><var>data_out</var>,
<strong>target_task</strong><var>data_count</var><strong>);</strong></pre><h4>Overwrite form:</h4><pre><strong>kern_return_t vm_read_overwrite</strong><strong>(vm_task_t</strong><var>target_task</var>,
<strong>vm_address_t</strong><var>address</var>,
<strong>vm_size_t</strong><var>size</var>,
<strong>pointer_t</strong><var>data_in</var>,
<strong>target_task</strong><var>data_count</var><strong>);</strong></pre><h3>PARAMETERS</h3><dl><p><dt><var>target_task</var><dd>
[in task send right]
The port for the task whose memory is to be read.
<p><dt><var>address</var><dd>
[in scalar]
The address at which to start the read.
<p><dt><var>size</var><dd>
[in scalar]
The number of bytes to read.
<p><dt><var>data_out</var><dd>
Out-pointer to dynamic array of bytes returned by the read.
<p><dt><var>data_in</var><dd>
In-pointer to array of bytes that will be overwritten with the data returned by the read.
<p><dt><var>data_count</var><dd>
[in/out scalar]
On input, the maximum size of the buffer; on output, the
size returned (in natural-sized units).
</dl><h3>DESCRIPTION</h3><p>
The <strong>vm_read</strong> and <strong>vm_read_overwrite</strong>
functions read a portion of a task's virtual
memory (they enable tasks to read other tasks' memory).
The <strong>vm_read</strong> function returns the data in a dynamically
allocated array of bytes; the <strong>vm_read_overwrite</strong> function
places the data into a caller-specified buffer (the <var>data_in</var>
parameter).
<h3>NOTES</h3><p>
This interface is machine word length specific because of the virtual address
parameter.
<h3>RETURN VALUES</h3><dl><p><dt><strong>KERN_PROTECTION_FAILURE</strong><dd>
Specified memory is valid, but does not permit reading.
<p><dt><strong>KERN_INVALID_ADDRESS</strong><dd>
The address is illegal or specifies a non-allocated region, or there are
less than <var>size</var> bytes of data following the address, or the region
specified by the <var>data_in</var> parameter cannot be written to.
</dl><h3>RELATED INFORMATION</h3><p>
Functions:
<a href="vm_copy.html"><strong>vm_copy</strong></a>,
<a href="vm_deallocate.html"><strong>vm_deallocate</strong></a>,
<a href="vm_write.html"><strong>vm_write</strong></a>.